The present invention relates to bearings and more particularly to spherical bearings.
Spherical bearings are well known in the prior art. In general, spherical bearings are formed with a spherical inner ball and a fixed outer race. The spherical surface of the inner ball abutts and is supported by a complimentary concave bearing surface on the outer race. In general this arrangement supports the inner ball for universal movement with respect to the outer race. Members that are attached to the inner ball can thus be supported for relatively complicated universal movements.
A shaft for example, may be attached to the spherical inner ball and supported for full rotation around its longitudinal axis while at the same time being supported for displacement through an angle of misalignment generally perpendicular to the plane of a stationary support member.
In the simplest spherical bearing design, the generally concave outer race is assembled around the generally spherical inner ball with the bearing elements in direct metal to metal contact. This design is satisfactory for some applications but is prone to high friction, excessive wear, and dirt contamination, especially under high loads and rpm's. In addition, the outer race is most often assembled from two pieces, which creates a sharp seam on the bearing surface. This seam adds to friction and wear on the bearing surfaces.
Another type of spherical bearing commonly known as the "messerschmidt" bearing utilizes complimentary slots on the spherical inner ball and on the outer race. Two small ball bearings are retained within the slots and support the relative motion of the inner ball and outer race. This arrangement provides less friction than metal to metal contact but is still subject to excessive wear due to the sharp edges of the slots and the relatively small bearing surface.